Researchers have reportedly found the remains of what would be the oldest human fossil discovered outside Africa, but not everyone is convinced.

Archaeologists have published a paper in Nature to announce a discovery that, if true, would rewrite a major chapter in human history.

The team from the University of Tübingen in Germany writes that a fragment of human skull unearthed from a cave in Greece decades ago has been dated to 210,000 years ago.

Chiselled out of a lump of rock found in the Apidima Cave located on the Mani peninsula, this dating of the fragment would make it the oldest Homo sapiens fossil discovered outside of Africa by more than 160,000 years. The skull fragment was originally discovered as part of an excavation in 1971 just inches away from a second, more intact skull.

The second skull was later studied in great detail and found to be that of a Neanderthal, while the more fragmented skull was largely ignored until this latest discovery.

According to The Guardian, Katerina Harvati, director of palaeoanthropology at the University of Tübingen in Germany, said that the skull is evidence that a small group of modern humans had pushed out from Africa further and earlier than we once thought.

Evidence for such failed excursions outside of Africa by bands of humans have been discovered before, most notably in modern-day Israel. While pioneers for their time, palaeontologists generally believe that they died out without leaving any genetic legacy.

The Apidima 2 cranium (right) and its reconstruction (left). Apidima 2 shows a suite of features characteristic of Neanderthals, indicating that it belongs to the Neanderthal lineage. Image: Katerina Harvati/Eberhard Karls/University of Tübingen

‘Extraordinary claims require extraordinary proofs’

It was only after such attempts that a human exodus from Africa, approximately 70,000 years ago, resulted in our species spreading across the globe.

When doing a comparative analysis between the Neanderthal and alleged human skull, Harvati and her team said the rounded back and lack of bulge usually associated with a Neanderthal were not present in the fragmented skull.

However, this latest discovery has raised a number of questions from the wider scientific community who feel such a remarkable claim could be a little too remarkable.

One of the major concerns is that the two skulls and surrounding material that were dated using uranium decay measurements show wildly different results. While the Homo sapiens skull is dated as being 210,000 years old, the Neanderthal skull is at least 170,000 years old and the rock that encased it is said to be more than 150,000 years old.

Juan Luis Arsuaga, a Spanish paleoanthropologist, said the skull is too incomplete to make any strong claim about its species or date.

“In science, extraordinary claims require extraordinary proofs. A partial braincase, lacking the cranial base and the totality of the face, is not extraordinary evidence to my mind.”